xoptional_assembly_base

Defined in xtensor/xoptional_assembly_base.hpp

template <class D>
class xt::xoptional_assembly_base

Base class for dense multidimensional optional assemblies.

The xoptional_assembly_base class defines the interface for dense multidimensional optional assembly classes. Optional assembly classes hold optional values and are optimized for tensor operations. xoptional_assembly_base does not embed any data container, this responsibility is delegated to the inheriting classes.

Template Parameters

Inherits from xt::xiterable< D >

Size and shape

auto size() const

Returns the number of element in the optional assembly.

constexpr auto dimension() const

Returns the number of dimensions of the optional assembly.

auto shape() const

Returns the shape of the optional assembly.

auto shape(size_type index) const

Returns the i-th dimension of the expression.

auto strides() const

Returns the strides of the optional assembly.

auto backstrides() const

Returns the backstrides of the optional assembly.

template <class S = shape_type>
void resize(const S &shape, bool force = false)

Resizes the optional assembly.

Parameters
  • shape: the new shape
  • force: force reshaping, even if the shape stays the same (default: false)

template <class S = shape_type>
void resize(const S &shape, layout_type l)

Resizes the optional assembly.

Parameters
  • shape: the new shape
  • l: the new layout_type

template <class S = shape_type>
void resize(const S &shape, const strides_type &strides)

Resizes the optional assembly.

Parameters
  • shape: the new shape
  • strides: the new strides

layout_type layout() const

Return the layout_type of the container.

Return
layout_type of the container

template <class T>
void fill(const T &value)

Fills the data with the given value.

Parameters
  • value: the value to fill the data with.

template <class S>
auto &reshape(const S &shape, layout_type layout)

Reshapes the optional assembly.

Parameters
  • shape: the new shape
  • layout: the new layout

Data

template <class… Args>
bool in_bounds(Args... args) const

Returns true only if the the specified position is a valid entry in the expression.

Return
bool
Parameters
  • args: a list of indices specifying the position in the expression.

template <class… Args>
auto operator()(Args... args)

Returns a reference to the element at the specified position in the optional assembly.

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal or greater than the number of dimensions of the optional assembly.

template <class… Args>
auto operator()(Args... args) const

Returns a constant reference to the element at the specified position in the optional assembly.

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal or greater than the number of dimensions of the optional assembly.

template <class… Args>
auto at(Args... args)

Returns a reference to the element at the specified position in the optional assembly, after dimension and bounds checking.

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal to the number of dimensions of the optional assembly.
Exceptions
  • std::out_of_range: if the number of argument is greater than the number of dimensions or if indices are out of bounds.

template <class… Args>
auto at(Args... args) const

Returns a constant reference to the element at the specified position in the optional assembly, after dimension and bounds checking.

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal to the number of dimensions of the optional assembly.
Exceptions
  • std::out_of_range: if the number of argument is greater than the number of dimensions or if indices are out of bounds.

template <class… Args>
auto unchecked(Args... args)

Returns a reference to the element at the specified position in the optional assembly.

Warning
This method is meant for performance, for expressions with a dynamic number of dimensions (i.e. not known at compile time). Since it may have undefined behavior (see parameters), operator() should be prefered whenever it is possible.
Warning
This method is NOT compatible with broadcasting, meaning the following code has undefined behavior: 
xt::xarray<double> a = {{0, 1}, {2, 3}};
xt::xarray<double> b = {0, 1};
auto fd = a + b;
double res = fd.uncheked(0, 1);
Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices must be equal to the number of dimensions of the optional assembly, else the behavior is undefined.

template <class… Args>
auto unchecked(Args... args) const

Returns a constant reference to the element at the specified position in the optional assembly.

Warning
This method is meant for performance, for expressions with a dynamic number of dimensions (i.e. not known at compile time). Since it may have undefined behavior (see parameters), operator() should be prefered whenever it is possible.
Warning
This method is NOT compatible with broadcasting, meaning the following code has undefined behavior: 
xt::xarray<double> a = {{0, 1}, {2, 3}};
xt::xarray<double> b = {0, 1};
auto fd = a + b;
double res = fd.uncheked(0, 1);
Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices must be equal to the number of dimensions of the optional assembly, else the behavior is undefined.

template <class S>
auto operator[](const S &index)

Returns a reference to the element at the specified position in the optional assembly.

Parameters
  • index: a sequence of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices in the list should be equal or greater than the number of dimensions of the optional assembly.

template <class S>
auto operator[](const S &index) const

Returns a constant reference to the element at the specified position in the optional assembly.

Parameters
  • index: a sequence of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices in the list should be equal or greater than the number of dimensions of the optional assembly.

template <class… Args>
auto periodic(Args... args)

Returns a reference to the element at the specified position in the optional assembly, after applying periodicity to the indices (negative and ‘overflowing’ indices are changed).

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal to the number of dimensions of the optional assembly.

template <class… Args>
auto periodic(Args... args) const

Returns a constant reference to the element at the specified position in the optional assembly, after applying periodicity to the indices (negative and ‘overflowing’ indices are changed).

Parameters
  • args: a list of indices specifying the position in the optional assembly. Indices must be unsigned integers, the number of indices should be equal to the number of dimensions of the optional assembly.

template <class It>
auto element(It first, It last)

Returns a reference to the element at the specified position in the optional assembly.

Parameters
  • first: iterator starting the sequence of indices
  • last: iterator ending the sequence of indices The number of indices in the sequence should be equal to or greater than the number of dimensions of the optional assembly.

template <class It>
auto element(It first, It last) const

Returns a constant reference to the element at the specified position in the optional assembly.

Parameters
  • first: iterator starting the sequence of indices
  • last: iterator ending the sequence of indices The number of indices in the sequence should be equal to or greater than the number of dimensions of the optional assembly.

Broadcasting

template <class S>
bool broadcast_shape(S &shape, bool reuse_cache = false) const

Broadcast the shape of the optional assembly to the specified parameter.

Return
a boolean indicating whether the broadcasting is trivial
Parameters
  • shape: the result shape
  • reuse_cache: parameter for internal optimization

template <class S>
bool has_linear_assign(const S &strides) const

Checks whether the xoptional_assembly_base can be linearly assigned to an expression with the specified strides.

Return
a boolean indicating whether a linear assign is possible

auto value()

Return an expression for the values of the optional assembly.

auto value() const

Return a constant expression for the values of the optional assembly.

auto has_value()

Return an expression for the missing mask of the optional assembly.

auto has_value() const

Return a constant expression for the missing mask of the optional assembly.

Public Functions

template <layout_type L>
auto begin()

Returns an iterator to the first element of the expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto begin(const S &shape)

Returns an iterator to the first element of the expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto begin() const

Returns a constant iterator to the first element of the expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto begin(const S &shape) const

Returns a constant iterator to the first element of the expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto end()

Returns an iterator to the element following the last element of the expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto end(const S &shape)

Returns an iterator to the element following the last element of the expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto end() const

Returns a constant iterator to the element following the last element of the expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto end(const S &shape) const

Returns a constant iterator to the element following the last element of the expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto rbegin()

Returns an iterator to the first element of the reversed expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto rbegin(const S &shape)

Returns an iterator to the first element of the reversed expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto rbegin() const

Returns a constant iterator to the first element of the reversed expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto rbegin(const S &shape) const

Returns a constant iterator to the first element of the reversed expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto rend()

Returns an iterator to the element following the last element of the reversed expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto rend(const S &shape)

Returns an iterator to the element following the last element of the reversed expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L>
auto rend() const

Returns a constant iterator to the element following the last element of the reversed expression.

Template Parameters
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.

template <layout_type L, class S>
auto rend(const S &shape) const

Returns a constant iterator to the element following the last element of the reversed expression.

The iteration is broadcasted to the specified shape.

Parameters
  • shape: the shape used for broadcasting
Template Parameters
  • S: type of the shape parameter.
  • L: order used for the traversal. Default value is XTENSOR_DEFAULT_TRAVERSAL.